﻿using System;

using System.Security.Cryptography;
using System.IO;

//using System.Collections.Generic;
//using System.Text;
//using System.Runtime.InteropServices;

namespace PockeTwit
{
    public interface IBindesh
    {
        string Encode(string str);
        string Decode(string str);
    }

    public class EncryptionDecryption// : IBindesh
    {
        /*
        public string Encode(string str)
        {
            string htext = "";

            for (int i = 0; i < str.Length; i++)
            {
                htext = htext + (char)(str[i] + 10 - 1 * 2);
            }
            return htext;
        }

        public string Decode(string str)
        {
            string dtext = "";

            for (int i = 0; i < str.Length; i++)
            {
                dtext = dtext + (char)(str[i] - 10 + 1 * 2);
            }
            return dtext;
        }
        */

        //const string KEY_64 = "VavicApp";//注意了，是8个字符，64位
        //const string IV_64 = "VavicApp";
        const string KEY_64 = "WeGooApp";//注意了，是8个字符，64位
        const string IV_64 = "WeGooApp";

        public static string Encode(string data)
        {
            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64);
            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64);

            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
            int i = cryptoProvider.KeySize;
            MemoryStream ms = new MemoryStream();
            CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateEncryptor(byKey,byIV), CryptoStreamMode.Write);

            StreamWriter sw = new StreamWriter(cst);
            sw.Write(data);
            sw.Flush();
            cst.FlushFinalBlock();
            sw.Flush();
            return Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);
        }

        public static string Decode(string data)
        {
            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64);
            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64);

            byte[] byEnc;
            try
            {
                byEnc = Convert.FromBase64String(data);
            }
            catch
            {
                return null;
            }

            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
            MemoryStream ms = new MemoryStream(byEnc);
            CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateDecryptor(byKey,byIV), CryptoStreamMode.Read);
            StreamReader sr = new StreamReader(cst);
            return sr.ReadToEnd();
        }
    }

}
